This is a optional HUDY Machined Aluminum Single Arm Servo Horn, and is intended for use with KO Propo, JR, Sanwa and Airtronics servos. These CNC-machined aluminum servo horns can be used with steering servos on any 1/8 off-road car. The aluminum servo horn offers maximum steering control by eliminating the flex often associated with composite servo horns. Drilled and tapped for 3mm-linkage hardware and two holes for linkage mounting, so you can quickly and easily change the linkage angle.